/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core.construction;



import com.bff.gaia.unified.sdk.runners.AppliedPTransform;

import com.bff.gaia.unified.sdk.transforms.PTransform;

import com.bff.gaia.unified.sdk.values.PValue;

import com.bff.gaia.unified.sdk.values.TupleTag;

import com.bff.gaia.unified.vendor.guava.com.google.common.collect.ImmutableList;



import java.util.Collection;

import java.util.Map;



import static com.bff.gaia.unified.vendor.guava.com.google.common.base.Preconditions.checkArgument;



/** Utilities for extracting subsets of inputs from an {@link AppliedPTransform}. */

public class TransformInputs {

  /**

   * Gets all inputs of the {@link AppliedPTransform} that are not returned by {@link

   * PTransform#getAdditionalInputs()}.

   */

  public static Collection<PValue> nonAdditionalInputs(AppliedPTransform<?, ?, ?> application) {

    ImmutableList.Builder<PValue> mainInputs = ImmutableList.builder();

    PTransform<?, ?> transform = application.getTransform();

    for (Map.Entry<TupleTag<?>, PValue> input : application.getInputs().entrySet()) {

      if (!transform.getAdditionalInputs().containsKey(input.getKey())) {

        mainInputs.add(input.getValue());

      }

    }

    checkArgument(

        !mainInputs.build().isEmpty() || application.getInputs().isEmpty(),

        "Expected at least one main input if any inputs exist");

    return mainInputs.build();

  }

}